Yifei Zhang

Increasing soil salinization in the Songnen Plain region, Northeast China, has hindered common bean ( Phaseolus vulgaris L.) cultivation. The specific regulatory mechanisms of sugar metabolism in common bean leaves under alkaline salt stress remain unclear. To address this research gap, in China's Songnen Plain, we subjected the high‐yielding and multi‐resistant granular bean variety “Qingyun 1” seedlings to stress treatments at 0, 24, and 48 h time points. Alkaline salt stress was simulated by applying 100 mM NaHCO ₃ and Na ₂ CO ₃ mixed at a 9:1 M ratio. With prolonged treatment time, common bean leaves gradually wilted and yellowed. Stomatal conductance, total chlorophyll, and carotenoids significantly decreased by 16.45%–75.77%. Superoxide dismutase, peroxidase, and catalase activities and malondialdehyde and H ₂ O ₂ contents significantly increased by 42.04%–91.36%, all reaching extremely significant levels ( p < 0.01). Under progressive photosynthesis inhibition, the dynamic regulatory network of sugar metabolism helped sustain common bean leaf responses to alkaline salt stress. Integration of the dynamic changes in the activities of hexokinase (HK), α‐galactosidase (galA), and 6‐phosphofructokinase with the levels of sugars resulted in persistently suppressed HK phosphorylation, enhancing galA activity accelerated stachyose and raffinose metabolism and Suc and Fru release promotion in the leaves under alkaline salt stress. This ensured sustained high SS concentrations, ultimately providing plants with additional energy and carbon sources. Thus, the key genes encoding galA could be important candidates for exploring alkaline salt stress response mechanisms in common bean. These findings provide insights and theoretical support for breeding new alkaline salt‐tolerant common bean varieties.

Cold stress critically restricts maize seedling growth in Northeast China, yet the mechanism by which cold priming (CP) enhances cold tolerance through proline–nitrogen metabolic networks remains unclear. This study systematically investigated CP’s synergistic regulation in cold-tolerant (Heyu27) and cold-sensitive (Dunyu213) maize using a two-phase temperature regime (priming induction/stress response) with physiological and multivariate analyses. CP alleviated cold-induced photosynthetic inhibition while maintaining a higher chlorophyll and photosynthetic rate, though biomass responses showed varietal specificity, with Heyu27 minimizing growth loss through optimized carbon–nitrogen allocation. Antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were pre-activated during early stress, effectively scavenging reactive oxygen species (ROS) and reducing malondialdehyde (MDA) accumulation, with Heyu27 showing superior redox homeostasis. CP enhanced proline accumulation via bidirectional enzyme regulation (upregulating ∆¹-pyrroline-5-carboxylate synthase/reductase [P5CS/P5CR], inhibiting proline dehydrogenase [ProDH]) and reprogrammed nitrogen metabolism through glutamate dehydrogenase/isocitrate dehydrogenase (GDH/ICDH)-mediated ammonium conversion to glutamate, alleviating nitrogen dysregulation while supplying proline precursors. Principal component analysis revealed divergent strategies: Heyu27 prioritized proline–antioxidant synergy, whereas Dunyu213 emphasized photosynthetic adjustments. These findings demonstrate that CP establishes “metabolic memory” through optimized proline–nitrogen coordination, synergistically enhancing osmoregulation, reactive oxygen species (ROS) scavenging, and nitrogen utilization. This study elucidates C₄-specific cold adaptation mechanisms, advancing cold-resistant breeding and stress-resilient agronomy.

Melatonin (MT) is a crucial hormone that controls and positively regulates plant growth under abiotic stress, but the biochemical and physiological processes of the combination of melatonin seed initiation and exogenous spray treatments and their effects on maize germination and seedling salt tolerance are not well understood. Consequently, in this research, we utilized the maize cultivars Zhengdan 958 (ZD958) and Demeiya 1 (DMY1), which are extensively marketed in northeastern China’s high-latitude cold regions, to reveal the modulating effects of melatonin on maize salinity tolerance by determining the impacts of varying concentrations of melatonin on maize seedling growth characteristics, osmoregulation, antioxidant systems, and gene expression. The findings revealed that salt stress (100 mM NaCl) significantly inhibited maize seed germination and seedling development, which resulted in significant increases in the H₂O₂ and O₂⁻ content and decreases in the antioxidant enzyme activity and photosynthetic pigment content in maize seedlings. However, exogenous melatonin considerably reduced the development inhibition caused by salt stress in maize seedlings. Moreover, exogenous melatonin alleviated NaCl-induced membrane damage and oxidative stress, and reduced Na⁺ content and excessively large quantities of reactive oxygen species (ROS). In addition, exogenous melatonin increased antioxidant enzyme activity and the expression of the antioxidant enzyme genes ZmSOD4, ZmCAT2, and ZmAPX2. This study demonstrates the potential role of combined melatonin seed initiation and foliar spray treatments in mitigating the detrimental effects of salt stress on maize growth, giving a theoretical foundation to future research on the possible advantages of exogenous regulating chemicals in attaining sustainable production in salt-alkaline soils.

Background: In the realm of wheat seed germination, abiotic stresses such as salinity and high temperature have been shown to hinder the process. These stresses can lead to the production of reactive oxygen species, which, within a certain concentration range, may actually facilitate seed germination. γ-aminobutyric acid (GABA), a non-protein amino acid, serves as a crucial signaling molecule in the promotion of seed germination. Nevertheless, the potential of GABA to regulate seed germination under the simultaneous stress of heat and salinity remains unexplored in current literature. Methods: This study employed observational methods to assess seed germination rate (GR), physiological methods to measure H₂O₂ content, and the activities of glutamate decarboxylase (GAD), NADPH oxidase (NOX), superoxide dismutase (SOD), and catalase (CAT). The levels of ABA and GABA were quantified using high-performance liquid chromatography technology. Furthermore, quantitative real-time PCR technology was utilized to analyze the expression levels of two genes encoding antioxidant enzymes, MnSOD and CAT. Results: The findings indicated that combined stress (30 °C + 50 mM NaCl) decreased the GR of wheat seeds to about 21%, while treatment with 2 mM GABA increased the GR to about 48%. However, the stimulatory effect of GABA was mitigated by the presence of ABA, dimethylthiourea, and NOX inhibitor, but was strengthened by H₂O₂, antioxidant enzyme inhibitor, fluridone, and gibberellin. In comparison to the control group (20 °C + 0 mM NaCl), this combined stress led to elevated levels of ABA, reduced GAD and NOX activity, and a decrease in H₂O₂ and GABA content. Further investigation revealed that this combined stress significantly suppressed the activity of superoxide dismutase (SOD) and catalase (CAT), as well as downregulated the gene expression levels of MnSOD and CAT. However, the study demonstrates that exogenous GABA effectively reversed the inhibitory effects of combined stress on wheat seed germination. These findings suggest that GABA-induced NOX-mediated H₂O₂ signalling plays a crucial role in mitigating the adverse impact of combined stress on wheat seed germination. This research holds significant theoretical and practical implications for the regulation of crop seed germination by GABA under conditions of combined stress.

High abiotic stress can decrease germination rate (GR), whereas low salinity or heat stress can enhance GR. Under the dual stress conditions of salinity (50 mM NaCl) and high temperature (35°C), the influence of gamma-aminobutyric acid (GABA) on wheat seed germination was examined. Low salinity (50 mM NaCl) arrested GR at high temperatures (35°C), whereas exogenous GABA improved GR under combined salinity (50 mM NaCl) and high temperature (35°C) stress. Additionally, improved seed germination associated with GABA could be attenuated by abscisic acid (ABA), dimethylthiourea (a reactive oxygen species [ROS] scavenger), and diphenyliodonium or imidazole (two NADPH oxidase inhibitors). Conversely, GABA-enhanced germination could be improved further by H2O2, diethyldithiocarbamic acid (a superoxide dismutase [SOD] inhibitor), aminotriazole (a catalase [CAT] inhibitor), fluridone (an ABA inhibitor), or gibberellin. In addition, GABA reversed the reduced H2O2 and enhanced ABA accumulation in wheat seeds, and GABA accumulation and glutamate decarboxylase activities were improved by exogenous GABA. Inhibited SOD and CAT activities were potentially reversed by GABA via the upregulation of MnSOD and CAT expression levels. According to the results, elevated antioxidant enzyme activities and ROS mediated by NADPH oxidase are essential for enhancing wheat seed germination through the application of GABA under the conditions of combined salt and high-temperature stress.

The development and utilization of biomass can not only address the demand for low-carbon energy and reduce environmental pollution, but can also facilitate the achievement of carbon neutrality. However, there are many factors justifying the case for low utilization of agricultural residues. These factors could be well controlled by producing top-quality pellets. Production of pellets is generally accompanied by the problems of high energy consumption and serious mold wearing. To eliminate these deficiencies, pretreatment has attracted scholars’ attention. In this review, the effects of four pretreatments on the properties of pellets were assessed. Thermal pretreatment can improve the hydrophobicity of pellets, and optimize their properties, while degradation of diverse extractives is noteworthy. Hydrothermal pretreatment improves the physical properties of pellets, through the increase of polar functional groups on the surface of the biomass. Ultrasonic vibration-assisted (UV-A) pelleting produces pellets under low pressure without a heating process; however, it is still not applied to large-scale production. Supercritical fluid extraction can achieve the graded utilization of extracts and bioactive substances in biomass, and the residues can be subsequently utilized as pellet feedstock. Mild hydrothermal treatment is a promising approach to improving the quality of agricultural pellets. Additionally, the effects of process parameters on the physical and chemical properties of pellets should be systematically analyzed.

To explore the effects of iminodisuccinic acid (a chelating agent) on maize (Zea mays L.) seed germination under lead (Pb) stress, we comparatively analyzed the effects of applying different concentrations of iminodisuccinic acid (0, 5, 20, and 100 mmol·dm⁻³) and combined an addition of exogenous substances regulating reactive oxygen species production on maize seed germination, seedling growth, H₂O₂ content, NADPH oxidase activity, and antioxidant enzyme activities under Pb-stressed and Pb-free conditions. Iminodisuccinic acid (100 mmol·dm⁻³) significantly delayed seed germination under normal germination conditions and alleviated the inhibitory effects of Pb stress (20 mmol·dm⁻³) on seed germination. Under normal conditions (without Pb stress), the iminodisuccinic acid-induced inhibition of seed germination was enhanced by treatment with dimethylthiourea (a specific scavenger of reactive oxygen species) or diphenyleneiodonium chloride (a specific inhibitor of NADPH oxidase), but diminished by treatment with H₂O₂, CaCl₂, diethyldithiocarbamic acid (a specific inhibitor of superoxide dismutase), or aminotriazole (a specific inhibitor of catalase). Under Pb stress, iminodisuccinic acid partially eliminated the excessive H₂O₂ accumulation, improved superoxide dismutase and catalase activity, and weakened the high NADPH oxidase activity. In addition, Ca²⁺ chelation may be essential for maintaining the reactive oxygen species’ balance and improving seed germination and seedling growth by iminodisuccinic acid supplementation in maize under Pb stress. The proposed iminodisuccinic acid supplementation-based method improved maize seed germination in Pb-polluted soil.

Soil sodicity and salinization is a major issues concerning agricultural production in northeast China. The effects of six treatments—no tillage (NT), no tillage and subsoiling (NTS), rotary and ridge tillage (RT), rotary and ridge tillage and subsoiling (RTS), rotary and flat tillage (FT), and rotary and flat tillage and subsoiling (FTS)—on soil physical and chemical properties and yields were compared from 2016 to 2018. The results showed that compared with the RT treatment, which is the traditional tillage method in this area, and the FT treatment, the NT treatment increased the soil water content (SWC) during the first‐leaf growth stage (V1). The use of subsoiling increased the average daily temperature and the soil thermal time (TT_soil). Subsoiling contributed to the growth and development of deep roots and increased leaf area index (LAI) to intercept more radiation. The NTS treatment increased grain yield of maize (Zea mays L.) by 2.7–15.2%, nitrogen use efficiency (NUE) by 4.2–14.4%, and water use efficiency (WUE) by 5.4–16.5% compared with RT. In conclusion, NTS soil management practices appear to be a sustainable approach to farming in the semiarid region of the Songnen Plain.

Low temperature is one of the major abiotic stresses that restrict the growth and development of maize seedlings. Membrane lipid metabolism and remodeling are key strategies for plants to cope with temperature stresses. In this study, an integrated lipidomic and transcriptomic analysis was performed to explore the metabolic changes of membrane lipids in the roots of maize seedlings under cold stress (5°C). The results revealed that major extraplastidic phospholipids [phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidic acid (PA), and phosphatidylinositol (PI)] were dominant membrane lipids in maize root tissues, accounting for more than 70% of the total lipids. In the transcriptome data of maize roots under cold stress, a total of 189 lipid-related differentially expressed genes (DEGs) were annotated and classified into various lipid metabolism pathways, and most of the DEGs were enriched in the “Eukaryotic phospholipid synthesis” (12%), “Fatty acid elongation” (12%), and “Phospholipid signaling” (13%) pathways. Under low temperature stress, the molar percentage of the most abundant phospholipid PC decreased around 10%. The significantly up-regulated expression of genes encoding phospholipase [phospholipase D (PLD)] and phosphatase PAP/LPP genes implied that PC turnover was triggered by cold stress mainly via the PLD pathway. Consequently, as the central product of PC turnover, the level of PA increased drastically (63.2%) compared with the control. The gene-metabolite network and co-expression network were constructed with the prominent lipid-related DEGs to illustrate the modular regulation of metabolic changes of membrane lipids. This study will help to explicate membrane lipid remodeling and the molecular regulation mechanism in field crops encountering low temperature stress.